sensors Mode-S transponder
7821AA
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-657S · COMAC C-919
- Hex
- 7821AA
- Octal
- 36020652
- Decimal
- 7,872,938
- Country
- CN
- Tail
- B-657S
- Type
- C919
- Flights observed
- 23
- Distinct callsigns
- 8
- Country
- CN
- Last broadcast
- 9d ago
Last known position
Country allocation
The ICAO 24-bit address 7821AA falls within the block assigned to China (CN) by ICAO Annex 10, Volume III. Every aircraft registered in China receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.
Callsign history 8 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| CES721 | China Eastern Airlines | 8 | 2026-05-30 |
| CES722 | China Eastern Airlines | 6 | 2026-05-30 |
| CES5162 | China Eastern Airlines | 3 | 2026-05-26 |
| CES2270 | China Eastern Airlines | 2 | 2026-06-07 |
| CES5358 | China Eastern Airlines | 1 | 2026-05-02 |
| CES5349 | China Eastern Airlines | 1 | 2026-05-02 |
| CES5159 | China Eastern Airlines | 1 | 2026-05-08 |
| CES5120 | China Eastern Airlines | 1 | 2026-05-06 |
Recent flights last 23
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-07 | CES2270 | SZX → XIY | Jun 7, 04:50 UTC | Jun 7, 05:00 UTC | 10m |
| 2026-06-02 | CES2270 | SZX → XIY | Jun 2, 05:10 UTC | Jun 2, 05:25 UTC | 15m |
| 2026-05-30 | CES722 | HKG → SHA | May 30, 04:25 UTC | May 30, 04:50 UTC | 25m |
| 2026-05-30 | CES721 | SHA → HKG | May 30, 01:20 UTC | May 30, 02:30 UTC | 1h 10m |
| 2026-05-29 | CES721 | SHA → HKG | May 29, 04:35 UTC | May 30, 02:30 UTC | 21h 55m |
| 2026-05-29 | CES721 | SHA → HKG | May 29, 04:20 UTC | May 30, 02:30 UTC | 22h 10m |
| 2026-05-29 | CES721 | SHA → HKG | May 29, 02:05 UTC | May 29, 02:15 UTC | 10m |
| 2026-05-28 | CES722 | HKG → SHA | May 28, 04:20 UTC | May 28, 05:30 UTC | 1h 10m |
| 2026-05-28 | CES721 | SHA → HKG | May 28, 02:10 UTC | May 28, 02:25 UTC | 15m |
| 2026-05-26 | CES5162 | PEK → SHA | May 26, 10:44 UTC | May 26, 10:54 UTC | 10m |
| 2026-05-25 | CES5162 | PEK → SHA | May 25, 10:45 UTC | May 25, 10:55 UTC | 10m |
| 2026-05-18 | CES5162 | PEK → SHA | May 18, 10:50 UTC | May 18, 11:05 UTC | 15m |
| 2026-05-13 | CES722 | HKG → SHA | May 13, 04:25 UTC | May 13, 04:40 UTC | 15m |
| 2026-05-13 | CES721 | SHA → HKG | May 13, 02:20 UTC | May 13, 02:45 UTC | 25m |
| 2026-05-12 | CES722 | HKG → SHA | May 12, 04:25 UTC | May 12, 04:45 UTC | 20m |
| 2026-05-08 | CES5159 | SHA → PEK | May 8, 08:29 UTC | May 8, 08:40 UTC | 10m |
| 2026-05-06 | CES5120 | PEK → SHA | May 6, 09:15 UTC | May 6, 09:25 UTC | 10m |
| 2026-05-02 | CES5358 | SZX → SHA | May 2, 12:45 UTC | May 2, 12:55 UTC | 10m |
| 2026-05-02 | CES5349 | SHA → SZX | May 2, 10:10 UTC | May 2, 10:30 UTC | 20m |
| 2026-04-27 | CES722 | HKG → SHA | Apr 27, 04:25 UTC | Apr 27, 05:35 UTC | 1h 10m |
| 2026-04-27 | CES721 | SHA → HKG | Apr 27, 02:30 UTC | Apr 27, 02:55 UTC | 25m |
| 2026-04-25 | CES722 | HKG → SHA | Apr 25, 04:30 UTC | Apr 25, 04:45 UTC | 15m |
| 2026-04-25 | CES721 | SHA → HKG | Apr 25, 02:25 UTC | Apr 25, 02:50 UTC | 25m |
About Mode-S
A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.
Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.
Prefer a tail-number view? See the B-657S page for operator, model, and routing details .